Roller mills of the aforesaid type are well known in the art in a variety of constructions. As a rule these roller mills are constructed with two or three rollers or pairs of rollers. They are generally used for relatively high throughput capacities, particularly for crushing coal (in coal grinding plant) and cement materials (for the production of cement raw meal or for the fine crushing of cement clinker). In the roller mills designed for these applications the grinding rollers can be resiliently retained individually and independently of one another by one or more roller carriers, as can be seen inter alia from W. Duda "Cement-Data-Book", 3rd Edition, Volume 1, 1985, pages 228 to 243. In these known roller mill constructions relatively great forces occur in the grinding work, and as a result a relatively high expenditure on construction must be incurred for the construction and retention of the individual grinding rollers and for the roller carrier or carriers and the construction and retention of the grinding table.
Starting from the knowledge that on the basis of its crushing work a roller mill is particularly suitable for the preparation of samples (e.g. laboratory samples), for the grinding of coal, coke etc. for small firing and for other small grinding tasks for instance in the chemical industry (outside the cement sector), the object of the invention is to provide a roller mill which with an appropriate relatively small throughput capacity is distinguished by a comparatively simple design but very robust construction which is not very prone to disruption and thus can be produced at relatively low cost.
In EP-A No. 68 681 a roller mill is disclosed in which the grinding rollers are mounted on a common supporting frame and to judge by the drawings the spindles of the grinding roller could be rigidly connected to this common supporting frame, apart from the fact that in this publication nothing detailed is stated with regard to the construction and mounting of the supporting frame, as a result of which this known roller mill clearly does not fulfill the generic concept of the present invention to the fullest extent, and it is also to be stated that the appertaining drawing only shows the roller mill in a vertical sectional view, so that the question remains entirely open as to how large the number of grinding rollers used here is or should be. In any case this known roller mill should quite clearly be placed in the category explained above which is intended for relatively high throughput capacities.